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Topological quantum states of matter, characterized by geometrical features of electronic band structures, have been extensively studied. Among them, the topological electronic state with magnetic order remains elusive because of a scarce number of examples. Here we present experimental observations proving that the pyrochlore iridate, when electronically tuned, can be a topological Weyl semimetal as predicted by recent theories. We observe a sizable spontaneous Hall conductivity with minimal magnetization only within a few Kelvin below the all-in all-out magnetic ordering temperature. Our theoretical calculation, which is quantitatively consistent with the observation, suggests that the presence of linearly-dispersing crossing points (Weyl points), acting as a source/sink of a quantized magnetic flux, potentially gives rise to such an enormous effect. The manifestation of the salient Hall response provides one important example of topological states, which promotes a better understanding of Weyl semimetal and indicates the new research direction for the topological-materials design. Material with both topological state and magnetic order remains rare. Here, Ueda et al. observe a sizable spontaneous Hall conductivity with minimal magnetization at a few Kelvin below the all-in-all-out magnetic ordering temperature in the predicted magnetic Weyl semimetal R 2 Ir 2 O 7 .

Magnetic domain walls are boundaries between regions with different configurations of the same magnetic order. In a magnetic insulator, where the magnetic order is tied to its bulk insulating property, it has been postulated that electrical properties are drastically different along the domain walls, where the order is inevitably disturbed. Here we report the discovery of highly conductive magnetic domain walls in a magnetic insulator, Nd₂Ir₂O₇, that has an unusual all-in-all-out magnetic order, via transport and spatially resolved microwave impedance microscopy. The domain walls have a virtually temperature-independent sheet resistance of ∼1 kilohm per square, show smooth morphology with no preferred orientation, are free from pinning by disorders, and have strong thermal and magnetic field responses that agree with expectations for all-in-all-out magnetic order.

The interplay between electron correlation and spin–orbit coupling in solids has been proven to be an abundant gold mine for emergent topological phases. Here we report the results of systematic magnetotransport study on bandwidth-controlled pyrochlore iridates R 2 Ir 2 O 7 near quantum metal-insulator transition (MIT). The application of a magnetic field along [001] crystallographic direction ( H //[001]) significantly decreases resistivity while producing a unique Hall response, which indicates the emergence of the novel semi-metallic state in the course of the magnetic transformation from all-in all-out (AIAO, 4/0) to 2-in 2-out (2/2) spin configuration. For H //[111] that favours 3-in 1-out (3/1) configuration, by contrast, the resistivity exhibits saturation at a relatively high value typical of a semimetal. The observed properties can be identified to reflect the emergence of multiple Weyl semimetal states with varying numbers of Weyl points and line nodes in respective spin configurations. With tuning effective bandwidth, all these states appear to concentrate around the quantum MIT region, which may open a promising venue for topological phenomena and functions. The interplay between multiple electronic interactions in solid promotes the emergence of exotic phases. Here, Ueda et al . report magnetotransport study on pyrochlore iridates R 2 Ir 2 O 7 near quantum metal-insulator transition reflecting the emergence of multiple Weyl semimetal states.

Magnonic devices operating at terahertz frequencies offer intriguing prospects for high-speed electronics with minimal energy dissipation However, guiding and manipulating terahertz magnons via external parameters present formidable challenges. Here we report the results of magnetic Raman scattering experiments on the antiferromagnetic spin-orbit Mott insulator Sr 2 IrO 4 under uniaxial stress. We find that the energies of zone-center magnons are extremely stress sensitive: lattice strain of 0.1% increases the magnon energy by 40%. The magnon response is symmetric with respect to the sign of the applied stress (tensile or compressive), but depends strongly on its direction in the IrO 2 planes. A theory based on coupling of the spin-orbit-entangled iridium magnetic moments to lattice distortions provides a quantitative explanation of the Raman data and a comprehensive framework for the description of magnon-lattice interactions in magnets with strong spin-orbit coupling. The possibility to efficiently manipulate the propagation of terahertz magnons via external stress opens up multifold design options for reconfigurable magnonic devices. There has been significant interest in using spin-waves or magnons for information processing, due to their low energy dissipation and short wavelength at terahertz frequencies, however, manipulating magnons can be challenging. Here, Kim et al show that magnons in Sr2IrO4 are extremely strain sensitive, with small applied strains leading to large variation in the magnon energy.

The discovery of topological insulators and semimetals triggered enormous interest in exploring emergent electromagnetic responses in solids. Particular attention has been focused on ternary half-Heusler compounds, whose electronic structure bears analogy to the topological zinc-blende compounds while also including magnetic rare-earth ions coupled to conduction electrons. However, most of the research in this system has been in band-inverted zero-gap semiconductors such as GdPtBi, which still does not fully exhaust the large potential of this material class. Here, we report a less-studied member of half-Heusler compounds, HoAuSn, which we show is a trivial semimetal or narrow-gap semiconductor at zero magnetic field but undergoes a field-induced transition to a Weyl semimetal, with a negative magnetoresistance exceeding four orders of magnitude at low temperatures. The combined study of Shubnikov-de Haas oscillations and first-principles calculation suggests that the exchange field from Ho 4 f moments reconstructs the band structure to induce Weyl points which play a key role in the strong suppression of large-angle carrier scattering. Our findings demonstrate the unique mechanism of colossal negative magnetoresistance and provide pathways towards realizing topological electronic states in a large class of magnetic half-Heusler compounds. Half-Heusler alloys containing rare earth ions have attracted interest due to combination of band-inversion and magnetism. Ueda et al study less studied trivial semiconductor HoAuSn, and show that it undergoes a magnetic field induced transition to a Weyl semimetal state, with a large reduction in the resistance.

Background Diffuse idiopathic skeletal hyperostosis (DISH) is a degenerative condition characterized by progressive ossification of anterior longitudinal ligaments, creating rigid spinal segments that act as lever arms susceptible to traumatic forces. The resulting fused segments restrict spinal flexibility and increase fracture instability compared to normal spine. While cervical DISH (c DISH) is known to be associated with increased paralysis severity and high mortality rates, the impact of DISH not extending to the cervical region (non-c DISH) on cervical spinal cord injury (SCI) severity remains unexplored. We investigated the relationship between non-c DISH and paralysis severity in cervical SCI patients. Methods Among 516 cervical SCI patients (2011–2023), 403 who underwent whole-spine CT and had classifiable ASIA impairment scales were included. DISH prevalence in thoracic, cervicothoracic, thoracolumbar, and whole-spine regions was examined. Relationships between DISH presence, age > 65 years, high-energy trauma, sex, cervical OPLL, and severe paralysis (ASIA grades A-B) were analyzed using ANOVA. Multivariate logistic regression explored associations between severe paralysis and c DISH/non-c DISH after Bonferroni correction. Results DISH prevalence was 21.1% (thoracic), 5.7% (cervicothoracic), 7.9% (thoracolumbar), and 2.2% (whole spine). Significant differences in ASIA impairment scale distribution were observed between DISH and non-DISH groups ( P  < 0.05). Multivariate analysis revealed significant associations between severe paralysis and DISH presence (OR 2.03, 95% CI 1.20–3.42) and male sex (OR 2.00, 95% CI 1.00-4.02). Both c DISH and non-c DISH were associated with severe paralysis compared to no DISH (c DISH: OR 4.56, 95% CI 2.09–9.96, P  < 0.001; non-c DISH: OR 1.76, 95% CI 1.01–3.06, P  < 0.05). Conclusions This study demonstrates that non-c DISH significantly increases the risk of severe cervical SCI, suggesting that thoracolumbar rigidity may biomechanically compromise cervical spine vulnerability during trauma. These findings have important clinical implications for risk assessment and management strategies in DISH patients sustaining cervical injuries.

Microglia, the resident immune cells in the central nervous system, play important roles not only in immune response but also in neurogenesis, synaptogenesis, and neural circuit formation. Microglia also surveil the brain environment via elongation and retraction of their processes. Previously, we found that the purine salvage pathway is involved in the regulation of morphology and dynamics of the microglial cell line BV2. Here, we show that intraperitoneal administration of mycophenolate mofetil (MMF), an inosine monophosphate dehydrogenase (IMPDH) inhibitor, reduces microglial branching during postnatal development. Imaging mass spectrometry analysis revealed that MMF administration decreases guanosine nucleotides in the brain. Interestingly, despite the essential role of guanosine nucleotides in cellular proliferation, MMF administration did not significantly affect microglial proliferation. On the other hand, MMF administration attenuated the level of GTP-bound forms of RhoA and Rac1 small GTPases. Notably, MMF administration decreased the number of branches, while process length remained unaffected. Since microglial branching affects microglial complexity and diversity, our findings suggest that guanosine nucleotide production is essential for generating proper microglial diversity.

Background The utility of resuscitative endovascular balloon occlusion of the aorta (REBOA) in children remains unclear. Case Presentation An 11‐year‐old patient with liver trauma with massive extravasation was transported to a local hospital, where an emergency trauma surgery was unavailable. Following the placement of REBOA as a bridge to hemostasis, she was transferred to our hospital by a firefighting helicopter with balloon occlusion. Immediately, she underwent damage control laparotomy and transcatheter arterial embolization. She was subsequently discharged from the hospital 6 months after the accident without complications. Conclusion REBOA as a bridge to hemostasis may be useful for pediatric patients. An 11‐year‐old patient with liver trauma underwent resuscitative endovascular balloon occlusion of the aorta (REBOA) inflation during air transportation. REBOA as a bridge to hemostasis may be useful for pediatric patients.

Background Early surgical decompression for traumatic cervical spinal cord injury has been associated with improved neurological outcomes, but because of heterogeneity across studies there is debate about the optimal timing. Multicenter investigations perhaps offer broad generalizability, but they may lack uniform perioperative management. In this single-center retrospective cohort study, we evaluated the association between surgical timing (within or beyond 24 h) and short-term outcomes under a standardized institutional protocol. Methods This study was conducted at a tertiary emergency and critical care center in Japan using a cohort of patients from between 2011 and 2024. Among 512 patients with traumatic cervical spinal cord injury, 337 underwent surgical decompression and/or stabilization and they were included in the analysis. Patients were categorized into early (<  24 h) and delayed (≥  24 h) surgery groups. Propensity score matching was applied (1:1 nearest neighbor, caliper 0.1) using sex, age, BMI, ASA class, ASIA grade, injury level, injury severity score, cervical dislocation, and procedure type. The primary outcome was neurological improvement at 30 days (≥ 1 ASIA grade). Secondary outcomes were overall complications and respiratory complications within 30 days. Logistic regression analyses were used to identify factors associated with the outcomes. Results Before matching, early surgery was associated with younger age, lower injury severity scores, and more severe neurological impairment. After propensity score matching, 100 matched pairs achieved covariate balance (standardized mean differences < 0.1–0.2). Early surgery was associated with greater neurological improvement (36.0% vs. 23.0%, p  = 0.044) and fewer overall complications (31.0% vs. 57.0%, p  < 0.001). Respiratory complications showed a trend toward reduction (19.0% vs. 29.0%, p  = 0.098). In multivariate analyses, early surgery was independently associated with neurological improvement (OR 2.39, 95% CI 1.19–4.81, p  = 0.014) and with reduced complications (OR 0.46, 95% CI 0.21–0.99, p  = 0.048). Conclusions Early surgical intervention within 24 h after traumatic cervical spinal cord injury was independently associated with improved neurological recovery and reduced short-term complications. These findings support prioritization of early decompression in institutions where surgery within 24 h is possible. Trial registration This study was approved by the Wakayama Medical University Institutional Review Board (Approval No. 4618).

PurposeDecision making in management of blunt bowel and mesenteric injury (BBMI) is difficult. This study aimed to identify indicators for laparotomy and appropriate time intervals to surgery.MethodsWe retrospectively reviewed our hospital’s trauma registry to identify patients with a diagnosis of BBMI from February 2011 to July 2017. Patients requiring therapeutic surgical treatment (OM group) were compared with those who did not (NOM group). Preoperative risk factors for surgery (with p < 0.1 by univariate analysis) were integrated in a multivariate logistic regression model. In the OM group, we identified relevant factors for time intervals to surgical interventions.ResultsAmong 2808 trauma patients admitted to our hospital, 83 (3.0%) had bowel and mesenteric injury; 6 patients with penetrating trauma, 2 lethal, untreated cases, and 2 patients who underwent exploratory laparotomy were excluded. Finally, 73 patients (47 males), with a mean Injury Severity Score (ISS) of 23, were included. Results from univariate analysis identified three relevant factors between the OM and NOM groups: ISS score (p = 0.036), hemodynamic instability (p = 0.041), and free air (p = 0.0018). Multivariate analysis revealed one relevant factor, free air (p = 0.0002). Short intervals between hospital admission and intervention were associated with 7-day mortality (p = 0.029), hemodynamic instability (p = 0.0009), focused assessment with sonography for trauma positive (p < 0.0001), and mesenteric extravasation (p = 0.012).ConclusionsEarly surgical intervention is essential in cases of hemodynamically unstable BBMI and bowel perforation with free air; nevertheless, it is associated with high mortality. We suggest that prompt transport along with early intervention could significantly lessen mortality.